The present invention relates to physically deleting the content of a file recorded in a tape medium (a tape, a medium) in a tape apparatus (tape drive).
A tape drive is used as a storage apparatus for recording information as a backup in a tape for a long period. IBM publishes the format of a file system for a tape drive called a linear tape file system (LTFS), and publishes the codes thereof in an open source manner. The LTFS divides a tape medium into two regions of an index partition (IP) and a data partition (DP). Meta-information (index) such as a file name is mainly recorded in the former, and the main body of a file is mainly recorded in the latter. In the case where a file stored in the tape medium is deleted using the LTFS, information concerning the file is deleted from the index in the IP. Even if the file is deleted, data that is stored in the DP and corresponds to the main body of the file continues to remain. This means that, even after the file is deleted, it is technically possible to read the data corresponding to the main body of the deleted file.
From the perspective of data security, after a user who uses the LTFS delivers data using a tape medium for the purpose of data exchange between companies or the like, the user desires to prevent the data on the medium from being read. A SCSI command called Long Erase is exemplified as a function of preventing the data written on the tape medium from being read. According to this command, a high frequency pattern is written from a location designated by the user to a tail portion of the partition, whereby the previously recorded data can be prevented from being read. If data recorded in a head portion of the DP is deleted using Long Erase, approximately three hours are required, because of such a mechanism that the data is deleted over the entire tape length. This required time is unavoidable in order to delete every data recorded over the entire tape length.